October 7: Luna

7October 7 1959 marks the day that one of humanity’s great mysteries was lifted; we saw what lies on the other side of the Moon.

liftoffWhat was remarkable was that in the thick of the Cold War, it was the Russians and not their American rivals who performed this extraordinary feat, seemly impossible in the context of 1959 technology and a mere two years, almost to the day of having launched Sputnik 1.

The pictures had to be taken on photographic film, automatically developed in a mini-photo-lab in space, and then scanned and transmitted back to Earth!

luna-3-cameraFilm was chosen for its superior resolution and fast recording and an emulsion selected that could be developed at any temperature.

Video, which was low in resolution was used only later on the 1960 Vostok missions when 400 line television system had been developed.  Videcon television tubes were notoriously unreliable, with pincushion distortion and were very slow to capture images, and would have to have scanned the scene, resulting in distortion.

The enormous amount of visual information that could be stored on a roll of film could be repeatedly rewound and scanned at whatever rate was convenient for telemetry transmission. The American Lunar Orbiter missions adopted the same strategy six years later.

The Russian Luna 3 was launched on a  Luna 8K72 (number I1-8) rocket over the North Pole to put Luna 3 on its course to the Moon, however the signal from the space probe was only about half as strong as expected, so the spacecraft spin axis was reoriented and some equipment was shut down to drop the temperature inside from 40 °C to a more workable  30 °C. When 60,000 to 70,000 km from the Moon, the orientation system was turned on and the spacecraft rotation was stopped. The lower end of the craft was pointed at the Sun, which was shining on the far side of the Moon.


At 14:16 UT on 6 October 1959, the space probe passed within 6,200 km of the Moon near its south pole at the closest lunar approach , and continued on over the far side. On 7 October, the photocell on the upper end of the space probe detected the sunlit far side of the Moon, and the photography sequence was started with a total of 29 pictures taken, covering 70% of the far side.. The first picture was taken at 03:30 UT at a distance of 63,500 km from the Moon, and the last picture was taken 40 minutes later from a distance of 66,700 km.

After several attempts to transmit the images it was only on October 18 that images were received, then all contact with the probe was lost on 22 October 1959.

moon-from-luna-3The photographs were taken with the Sun behind the craft and so are flatly lit, giving little surface relief. Nevertheless, they were an astounding revelation; the so-called Dark Side (not actually dark, but unseen), was devoid of the dark ‘mares’ or ‘seas’ seen on the near side. Why? The far side crust is 80 km thick but 60 km deep on the near side, so magma may have been prevented from reaching and flooding the surface as they did on the near side (the Mares). The asymmetry may be due to the slowing of the moon’s rotation into its present tidally-locked state with the Earth.

The entire ingenious, expensive exercise had as its goal to make a photograph of the unseen; a trophy in the Cold War, one that brought knowledge, but which came arguably at the price of the mystique of the Moon and its symbolic value.


3 thoughts on “October 7: Luna

  1. Great summary.
    Is it true, the Russians used captured “AB” (American Balloon) spy film, in Luna 3?
    Because of its radiation tolerance. I have read some definitive-sounding reports on that but am not sure it is true.


    1. Hi Erik, it’s certainly feasible, but we have only the testimony of Peter Bratslavets at http://www.svengrahn.pp.se/trackind/luna3/SpyBalloon.htm as to the truth of this story which he says emerged only because sufficient time had passed to ensure he would not be reprimanded for using film not of Soviet origin. Film had been used in high altitude balloons to measure cosmic radiation. The Wikipedia article mentions the Russians’ acquisition of the film from American Genetrix reconnaissance balloons but only gives a reference to transcription of Alan Bellows’ podcast at https://www.damninteresting.com/faxes-from-the-far-side/ which itself cites no references. The story reappears in ‘Avoiding Armageddon’ by Walter Sierra with some data on the number of spy balloon flights over Russia and the 6% that returned photographs (with the rest presumably falling into Russian hands or being lost)…but again, no references, as is the case with the account in all other books I can find. However, another feature of the film was its capacity not only to withstand the high temperatures it would be exposed to, but to handle high-temperature development; the latter not a feature needed for its use in reconnaissance balloons since the film was to be retrieved and presumably developed normally. That’s the only possible inconsistency I can find in what is a fascinating, but still somewhat outlandish tale.


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